Tannase activity from the marine cyanobacterium Phormidium valderianum BDU140441

The marine cyanobacterium Phormidium valderianum BDU 140441 exhibited the ability to grow at 0.25?mM tannic acid, a known hindering chemical for microbial growth. The tannic acid-degrading ability of the organism is evident from the UV–visible absorption spectrum. In addition, the existence of tannase has been localized by activity staining, and its induction in activity upon tannic acid exposure was confirmed in native gel. The critical tannic acid metabolization enzymes tested for are polyphenol oxidase and esterases; both are well known for tannic acid degradation. Upon tannic acid exposure, increased activity of polyphenol oxidase and expression of few new isoforms of esterase were identified by activity staining.     

Epitopes recognized by serum anti-α-galactoside antibody are present on brain glycoproteins in man

Naturally occurring serum IgG against terminal α-galactoside epitopes (anti-Gal), present exclusively in man, apes and old world monkeys, was used as probe for these epitopes in human brain. Human brain grey matter soluble glycoproteins enriched inα galactosyl groups by affinity chromatography on jacalin-sepharose, specifically binds to human anti-Gal in immuno dot blots. Anti-Gal recognized exclusively the terminal α galactoside epitope in human brain glycoproteins since binding was abolished by the presence of 1-0-methyl α-D-galactopyranoside as well as by pretreatment of glycoproteins with coffee bean α-galactosidase. Anti-Gal-peroxidase staining of jacalin-binding human brain glycoproteins in western immuno blots revealed mainly five anti-Gal-binding polypeptides withM _r (in kDa) of 94, 108, 180, 210 and 230 respectively. Since the presence of anti-Gal in higher animals accompanies suppression of the corresponding epitope in most tissues, apparently to maintain immunological balance, possible implications of the above observation for autoimmunity, tumor metastasis and infection are discussed.     

Engineered Silybin Nanoparticles Educe Efficient Control in Experimental Diabetes

Silybin, is one imminent therapeutic for drug induced hepatotoxicity, human prostrate adenocarcinoma and other degenerative organ diseases. Recent evidences suggest that silybin influences gluconeogenesis pathways favorably and is beneficial in the treatment of type 1 and type 2 diabetes. The compound however is constrained due to solubility (0.4 mg/mL) and bioavailabilty limitations. Appropriate nanoparticle design for silybin in biocompatible polymers was thus proposed as a probable solution for therapeutic inadequacy. New surface engineered biopolymeric nanoparticles with high silybin encapsulation efficiency of 92.11% and zeta potential of +21 mV were designed. Both the pure compound and the nanoparticles were evaluated in vivo for the first time in experimental diabetic conditions. Animal health recovered substantially and the blood glucose levels came down to near normal values after 28 days treatment schedule with the engineered nanoparticles. Restoration from hyperglycemic damage condition was traced to serum insulin regeneration. Serum insulin recovered from the streptozotocin induced pancreatic damage levels of 0.17±0.01 µg/lit to 0.57±0.11 µg/lit after nanoparticle treatment. Significant reduction in glycated hemoglobin level, and restoration of liver glycogen content were some of the other interesting observations. Engineered silybin nanoparticle assisted recovery in diabetic conditions was reasoned due to improved silybin dissolution, passive transport in nanoscale, and restoration of antioxidant status.     

Role of cytokines in experimentally induced lung cancer and chemoprevention by COX-2 selective inhibitor, etoricoxib

This study explored the role of pro- and anti-inflammatory cytokines in dimethyl benz(a)anthracene (DMBA)-induced lung cancer and its subsequent correction with a COX-2 inhibitory NSAID, etoricoxib. A single dose of DMBA (20?mg/kg body weight) in 0.9?% NaCl administered intratracheally was used to induce tumors in the rat lungs in 20?weeks. The study of pro-inflammatory cytokines like IL-1??, TNF-??, and IFN-?? revealed their upregulation by DMBA administration and restoration of their levels toward normal by the treatment with etoricoxib, while the anti-inflammatory cytokine IL-2 was found to be down-regulated with carcinogen administration and corrected with etoricoxib treatment. Apoptosis was studied by mitochondrial Bcl-2/Bax ratio and staining with fluorescent dyes acridine orange/ethidium bromide. The results showed a decreased apoptotic level with DMBA which was corrected with etoricoxib. Also, mitochondrial membrane potential was studied using JC-1 and rhodamine-123, which are membrane permeant fluorescent dyes, and generate information about cells at lower and higher mitochondrial membrane potential (???_M). The results showed the presence of maximum number of cells with higher ???_M in the DMBA group and their number was considerably lowered in the other three groups.     

Human Equilibrative Nucleoside Transporter-3 (hENT3) Spectrum Disorder Mutations Impair Nucleoside Transport,Protein Localization,and Stability

Accumulating evidence reveals that sole mutations in hENT3 cause a spectrum of human genetic disorders. Among these include H syndrome, characterized by scleroderma, hyperpigmentation, hypertrichosis, hepatomegaly, cardiac abnormalities and musculoskeletal deformities, pigmented hypertrichotic dermatosis with insulin-dependent diabetes syndrome, characterized by autoantibody-negative diabetes mellitus and skin deformities, familial Rosai-Dorfman disease, characterized by short stature, familial histiocytosis and sinus histiocytosis with massive lymphadenopathy (SHML), characterized by severe tissue infiltration of immune cells and swollen lymph nodes. hENT3 spectrum disorders share a common mutation and share overlapping clinical manifestations that display many intriguing resemblances to mitochondrial and lysosomal disorders. Although earlier studies identify hENT3 as a mitochondrial and a lysosomal nucleoside transporter, the precise connections between hENT3 and the pathophysiology of these disorders remain unresolved. In this study, we performed functional and biochemical characterization of these mutations in hENT3. We report severe reductions/losses of hENT3 nucleoside transport functions of hENT3 syndrome mutants. In addition to transport alterations, we provide evidence for possible loss of hENT3 functions in all H and pigmented hypertrichotic dermatosis with insulin-dependent diabetes syndromes due to either mistrafficking or altered stability of mutant hENT3 proteins.     

Histidine Residue Mediates Radical-induced Hinge Cleavage of Human IgG1

Hydroxyl radicals induce hinge cleavage in a human IgG1 molecule via initial radical formation at the first hinge Cys²³¹ followed by electron transfer to the upper hinge residues. To enable engineering of a stable monoclonal antibody hinge, we investigated the role of the hinge His²²⁹ residue using structure modeling and site-directed mutagenesis. Direct involvement of His²²⁹ in the reaction mechanism is suggested by a 75–85% reduction of the hinge cleavage for variants in which His²²⁹ was substituted with either Gln, Ser, or Ala. In contrast, mutation of Lys²²⁷ to Gln, Ser, or Ala increased hinge cleavage. However, the H229S/K227S double mutant shows hinge cleavage levels similar to that of the single H229S variant, further revealing the importance of His²²⁹. Examination of the hinge structure shows that His²²⁹ is capable of forming hydrogen bonds with surrounding residues. These observations led us to hypothesize that the imidazole ring of His²²⁹ may function to facilitate the cleavage by forming a transient radical center that is capable of extracting a proton from neighboring residues. The work presented here suggests the feasibility of engineering a new generation of monoclonal antibodies capable of resisting hinge cleavage to improve product stability and efficacy.     

EhCoactosin Stabilizes Actin Filaments in the Protist Parasite Entamoeba histolytica

Entamoeba histolytica is a protist parasite that is the causative agent of amoebiasis, and is a highly motile organism. The motility is essential for its survival and pathogenesis, and a dynamic actin cytoskeleton is required for this process. EhCoactosin, an actin-binding protein of the ADF/cofilin family, participates in actin dynamics, and here we report our studies of this protein using both structural and functional approaches. The X-ray crystal structure of EhCoactosin resembles that of human coactosin-like protein, with major differences in the distribution of surface charges and the orientation of terminal regions. According to in vitro binding assays, full-length EhCoactosin binds both F- and G-actin. Instead of acting to depolymerize or severe F-actin, EhCoactosin directly stabilizes the polymer. When EhCoactosin was visualized in E. histolytica cells using either confocal imaging or total internal reflectance microscopy, it was found to colocalize with F-actin at phagocytic cups. Over-expression of this protein stabilized F-actin and inhibited the phagocytic process. EhCoactosin appears to be an unusual type of coactosin involved in E. histolytica actin dynamics.     

Predicting the Distribution Pattern of Small Carnivores in Response to Environmental Factors in the Western Ghats

Due to their secretive habits, predicting the pattern of spatial distribution of small carnivores has been typically challenging, yet for conservation management it is essential to understand the association between this group of animals and environmental factors. We applied maximum entropy modeling (MaxEnt) to build distribution models and identify environmental predictors including bioclimatic variables, forest and land cover type, topography, vegetation index and anthropogenic variables for six small carnivore species in Mudumalai Tiger Reserve. Species occurrence records were collated from camera-traps and vehicle transects during the years 2010 and 2011. We used the average training gain from forty model runs for each species to select the best set of predictors. The area under the curve (AUC) of the receiver operating characteristic plot (ROC) ranged from 0.81 to 0.93 for the training data and 0.72 to 0.87 for the test data. In habitat models for F. chaus, P. hermaphroditus, and H. smithii “distance to village” and precipitation of the warmest quarter emerged as some of the most important variables. “Distance to village” and aspect were important for V. indica while “distance to village” and precipitation of the coldest quarter were significant for H. vitticollis. “Distance to village”, precipitation of the warmest quarter and land cover were influential variables in the distribution of H. edwardsii. The map of predicted probabilities of occurrence showed potentially suitable habitats accounting for 46 km² of the reserve for F. chaus, 62 km² for V. indica, 30 km² for P. hermaphroditus, 63 km² for H. vitticollis, 45 km² for H. smithii and 28 km² for H. edwardsii. Habitat heterogeneity driven by the east-west climatic gradient was correlated with the spatial distribution of small carnivores. This study exemplifies the usefulness of modeling small carnivore distribution to prioritize and direct conservation planning for habitat specialists in southern India.